Comparison of Clonidine with Fentanyl as an Adjuvant to Isobaric Ropivacaine in Patients undergoing Vaginal Hysterectomy under Subarachnoid Block

Background: Use of adjuncts to local anaesthetics improves the quality of subarachnoid block (SAB). We compared intrathecal clonidine-ropivacaine combination and fentanyl-ropivacaine combination for the quality and duration of sensory and motor block and associated side effects. Subjects and methods: 80 patients undergoing elective vaginal hysterectomy under SAB were enrolled for this hospital-based, prospective, randomized, double-blind study and divided into two groups of 40 each. As an adjuvant to 0.75% isobaric ropivacaine Group C received 75 μg intrathecal clonidine (0.5 ml) while Group F was given 25 μg intrathecal fentanyl (0.5 ml). Sensory and motor block characteristics, duration of analgesia, intraoperative and postoperative Campbell sedation score, haemodynamic profile and any adverse event were recorded and analysed. Fischer exact or Chi-square test was used for the comparison of categorical data and unpaired t-test to compare the quantitative data using Statistical Packages for Social Sciences (SPSS) version 21. P value of <0.05 was considered statistically significant. Results: Sensory and motor block duration, duration of analgesia, intraoperative and postoperative sedation score was significantly higher in Group C (P < 0.05). Systolic blood pressure, diastolic blood pressure and mean blood pressure were significantly lower in Group C as compared to Group F at various time points with a similar overall incidence of hypotension from the baseline value. Conclusion: Clonidine-ropivacaine combination in SAB provides a prolonged duration of sensory as well as motor block and enhances postoperative analgesia in comparison to fentanyl-ropivacaine combination with a higher degree of sedation.